Projectile with stabilizing surfaces



eco 2Q, H966 a. ca-m0wswz PROJECTILE WITH STABILIZING SURFACES 3 Sheets-4511961 Filed June 25, 1965 em, 2@, W66 c. CHILOWSKY 3, 3

PROJECTILE WITH STABILIZING SURFACES Filed June 25, 1965 3 Sheets-Sheet 2 Dec, 2Q, H966 c. CHELOWSKY 3,292,879

PROJEGTILE WITH STABILIZING SURFACES Filed June 25, 1965 5 Sheets-Sheet 3 United States Patent PROJECTELE WlTH STABILIZING SURFACES Constantin Chilowslry, deceased, late of New York, N.Y.,

by Willard Saxton Seward, executor, Morris Township,

N..l., assignor to Canrad Precision Industries, Inc.,

New York, N.Y., a corporation of Delaware Filed June 25, 1965, Ser. No. 467,145 7 Claims. (Cl 244l3.3)

This invention relates to projectiles and more particularly to stabilization of the latter in flight.

Projectiles equipped at their rear with stabilizing fins and fired from unrifled guns at relatively low initial velocities have proven themselves to possess considerable advantages over ordinary projectiles for rifled guns, particularly from the point of view of simplicity of gun construction and of greater precision of firing. For higher initial velocities, however, where values of from 800 to 1000 meters per second and higher are attained, great difliculties are encountered in stabilizing projectiles equipped with stationary stabilizing fins and fired from unrifled guns.

Conditions of great instability are created by the effect of the air compression wave, the enormous increase in air resistance in front of the projectile at such velocities, and the fact that the moment of inertia of the projectile with reference to the axis perpendicular to its trajectory remains approximately the same. Also, the partial vacuum which is created at the rear of the projectile and which is increased and extended with increased velocity, affects the efliciency of any fixed stabilizing surfaces. These conditions could be compensated for by expanding the stabilizing fins and making them so heavy and cumbersome that the actual manipulation of the projectiles and their loading would be made exceedingly difficult, if not impossible. However, when the velocity of the projectile exceeds the velocity of sound, large stabilizing surfaces or fins cannot be used; only small and thin stabilization surfaces appear to be compatible with supersonic velocities.

An object of this invention is to avoid the aforesaid difiiculties by providing projectiles equipped with stabilizing surfaces which are capable of remaining stable at very high initial velocities and which, at the same time, are of normal dimensions, do not occupy excessive space and which can be easily manipulated and loaded into a gun.

This invention covers projectiles of all calibers and particularly those of very small caliber consisting of bullets charged with explosives and used by aircraft in firing at other aircraft.

According to this invention the rear part of the projectile is equipped with stabilizing fins of relatively restricted or small dimensions. The assembled projectile, comparatively unencumbered in its shape, can be easily manipulated and loaded into the gun. The stabilizing fins at the rear of the projectile, suitably carried by support means, in most cases by a long axial spindle, are movable, together with the support means to emerge automatically from the projectile after firing (or in some cases during firing) to be thereafter carried at a considerable distance to the rear of the projectile.

Before firing, the axial spindle which carries the fins at its rear end, is enclosed and hidden inside the projectile. At the moment of firing, or immediately thereafter, the spindle is pushed very quickly rearwardly relative to the projectile, thereby causing the fins to take nearly instantaneously their extreme extended position at the rear of the projectile, while the front end of the supporting spindle is held in locked position in the base of the projectile. In this manner the fins are placed in a position which is relatively very far removed from the ice center of gravity and the center of pressure of the projectile, that is, to a position where they can exert the most efficient stabilizing and guiding action. Furthermore, at a distance to the rear of the projectile the aerodynamic conditions, under which the stabilizing fins have to perform their task, are more favorable. By means of these stabilizing surfaces of relatively small dimensions, a stabilizing influence is exerted which is exceedingly elfective and entirely adequate for very high initial velocities.

The invention further provides, in one or more embodiments, that the stabilizing fins in their initial retracted position are enclosed in the rear part of the projectiles body or inside special protecting devices attached to the rear of the projectile. The stabilizing fins can, whenever necessary, remain isolated from the dangerously violent destructive action of the powder gasses, and thereby can be made light so that their presence will not transfer the center of gravity of the projectile substantially toward its rear. The assembled projectile, in unfired condition, appears as an ordinary projectile, very compact and easily manipulated, which can be readily loaded into a gun, even through the breech. At the moment the projectile leaves the gun it is automatically transformed into an elongated arrow-like projectile having a remarkable ability for retaining its stability in flight.

In order to enclose and guide the fin-carrying spindle, a gas tight axial tube is provided in the projectile starting at its base and extending toward its front. The tube is preferably sealed in such a way that an absolutely tight seal is effected between the space occupied by the fincarrying spindle and the remaining volume of the projectile containing the explosive charge. In one embodiment, the extension of the fin carrying spindle may be realized by telescoping tubes, thus permitting a total extension greater than the length of the projectile.

Means are provided in this invention for an automatic extension or expulsion of the fin-carrying spindle from the projectile toward the rear thereof, this expulsion taking place generally at the moment the projectile has left the gun and the dangerous zone of powder gases. In certain cases, expulsion can take place inside the bore of the gun in such a way that a substantial expansion of powder gases takes place at a time when the projectile has already left the muzzle of the gun while the stabilizing fins have not. Among different means covered by this invention to cause this expulsion to take place, one is based on the inertia of the fin-carrying spindle and the establishment of a braking effect to stop the expulsion and reduce the shock, for example, in the case where the expulsion takes place inside the bore of a gun. In other embodiments the invention provides that this expulsion is produced by the action of compressed gases either developed, stored or introduced inside the axial protecting tube, described above, upon the fin-carrying spindle.

In explosive projectiles, and particularly in very small projectiles, or explosive bullets, the fin-carrying spindle is in most cases made hollow.

This invention provides furthermore for projectiles constructed in such a Way that a large part of their mass is shifted toward the front while the rear part is lightened, as well as for projectiles particularly long in proportion to their caliber. It also provides for the discharge of these projectiles to be made with the intermediary of a wad which will protect them from the direct action of powder gases.

A practical embodiment of the invention is shown in the accompanying drawings wherein:

FIG. 1 is an elevational view, partially in section, of a projectile constructed in accordance with this invention.

FIG. 2 is a bottom view of FIG. 1.

FIG. 3 is similar to FIG. 1 but shows the stabilizing fins in an extended position.

FIG. 4 is a partial sectional view, on an enlarged scale, of the forward section of the spindle.

FIG. 5 is an elevational view of the lower portion of the projectile shown in FIGS. 1 and 2.

FIG. 6 is a sectional view, on a larger scale, of a portion of the base of the projectile.

FIG. 7 is a bottom view of FIG. 6.

FIG. 8 is an elevational view, partially in section, of a modified form of the invention.

FIG. 9 is a bottom view of FIG. 8.

FIG. 10 is similar to FIG. 8 but shows the stabilizing fins in an extended position.

FIG. 11 is a partial sectional view, on an enlarged scale, of the forward part of the spindle used with the FIG. 8 embodiment.

FIG. 12 is a side view of the lower portion of FIG. 10.

FIG. 13 is a partial sectional view, on an enlarged scale, of a portion of the base of the projectile shown in FIGS. 8 and 10.

FIG. 14 is a sectional view of another modified version of the invention.

FIG. 15 is a partial view of yet another modified form of the invention.

FIG. 16 is a. partial view of a further modified form in which the spindle is withdrawn from the projectile by an air-actuated device.

FIG. 17 is a bottom view of the air actuated device shown in FIG. 16.

FIG. 18 is a perspective view of a further modified form of the invention in which the spindle is rotated as it is extended from the rear of the projectile.

FIG. 19 is a partial view of a further modified form employing a telescopic spindle.

Referring to the drawings, and particularly the embodiment shown in FIGS. 1 to 7, a projectile is shown as comprising a body 20 containing an explosive charge 22 and having a fuse with detonator 24 suitably affixed to the front end as by the threaded connection 26. The rear of the body 20 has a base 28 having a central opening in which is received an axial tube 30 for housing a movable means as the retractable spindle 32. This spindle 32 carries stabilizing surfaces or fins 34 at its rearward end and is withdrawn from the tube 30 after firing of the projectile so that the fins 34 will be carried at a rear position removed from the projectile, as shown in FIG. 3, to stabilize the projectile in flight.

The tube 30 is suitably affixed and sealed to the base 28 as by the threaded connection 36, thereby isolating and sealing the interior of the tube 30 from the explosive charge 22. The spindle 32 is hollow and of a slightly smaller diameter than the inside diameter of the tube 30. The forward end of the tube 30, however, has an enlarged section of bushing 38 suitably afiixed thereto as by welding and which is of a diameter approaching that of the inner diameter of the tube 30 to provide a sliding seal. At the base 28 of the projectile, there is provided within the tube 30 a bushing 40 made of a deformable material, e.g. copper. This bushing 40 has one or more concentric rings 42 to facilitate deforming of the bushing to arrest and support the spindle as will be further described.

A braking fluid, for example, a viscous material such as heavy oil, grease, or paste 46, is contained within the tube 30 exteriorly of the spindle 32 as best shown in FIG. 1. An axially extending groove or slot 44 in the inner face of the bushings 40 provides communication between the inside of the tube 30, exteriorly of the spindle 32, and the outside of the tube 30. The viscous braking fluid will not ordinarily flow through the relatively small groove 44 unless forced out under pressure.

The fins 34 are carried by a hub 48 suitably afifixed to the spindle 32. The hub 48 is hollow having its terminal end sealed as by the threaded fitting 49. Openings 50 are provided in the wall of the hub for reasons to be described.

In operation, upon firing of the projectile from the bore of a cannon or the like, the expanding gases of the explosive propellant charge (not shown) will pass through openings 50 in the hub 48 and thence through the interior of the spindle 32 into the tube 30. The gases from the ignited propellant charge will develop a pressure in the tube 30 such that as the projectile leaves the rifle bore, they will be effective to react against the spindle to extend or propel the latter rearwardly. As the spindle extends to the rear, the bushing 38 forces the fluid 44 out through the relatively small slot 44 to provide a braking effect. As the spindle reaches its extended position (FIG. 3) the bushing 38 seats against the bushing 40 to prevent further extension and also to support the spindle in its extended position. As previously mentioned the bushing 40 is made of a deformable material and is therefore crushed and deformed about the bushing 38 to lock the spindle in place in its extended position. With the spindle and stabilizing fins extended to the rear, the projectile will be stabilized in flight.

The stabilizing fins 34 in assuming their extreme position to the rear of the projectile, which position is relatively far removed from the center of gravity and the center of pressure of the projectile, are in a position where they can exert the most efficient stabilizing and guiding action. Futhermore, as previously explained, conditions are more favorable for the fins to provide the desired effect when they are disposed at this position.

In order to enclose the stabilizing fins 34 when the spindle 32 is within the tube 30, an enclosure 52 may be provided. This enclosure 52 is suitably affixed to the projectile as by the threaded connection 54 and has a rear section converging into a cross-shaped form having slots 56 for housing the stabilizing fins 34. This shape reduces the aerodynamic turbulence at the rear end of the projectile, and the fins in their extended position pass through a less turbulent air stream than would otherwise be the case with a blunt end. Accordingly, the cross-shape provides greater efficiency of stabilization.

It will be evident that the embodiment of FIGS. 1 to 7 may be operated without employing the fluid braking described above. In such a case, the requirement for the fluid 46 would be eliminated and the deforming of the bushing 40 as the spindle is propelled to the rear, would provide the necessary braking effect.

In the modified version of FIGS. 8 to 13, the spindle 57 is extended by gas pressure produced within the tube 58 rather than from an external source as in the embodiment of FIGS. 1 to 7. As shown in FIG. 8, the forward end of the spindle 57 has a chamber 59 containing a means for producing a gas under pressure as a powder charge 60. The powder charge 60 has a percussion cap 62. An actuating plunger 64, mounted for reciprocal movement in the chamber 59 is urged against a threaded bushing 66 by the bias of spring 67. Except at the time of firing of the projectile, the spring 67 biases the plunger 64 in a position remote from the percussion cap 62 (FIGS. 8 and 11) against the threaded bushing 66in the end of the spindle 57.

From the above description it will be readily evident that upon firing of the projectile, inertia will cause the plunger 64 to move rearwardly to overcome the bias of spring 67 and set off the percussion cap '62 and powder charge thereby developing sufficient gas pressure within the tube 58 to extend the spindle 57 rearwardly to the position shown in FIG. 10. The plunger 64 fits loosely in the spindle so that the gases can escape therearound into the tube 58. A small opening or passageway 70 is provided in the spindle 57 to exhaust the gases to the atmosphere after the spindle is extended. The gases passing through this passageway 70 into the annular space between the tube 58 and spindle 57 during extension of the latter will be compressed therein because of the enlargement 72 at the end of the spindle 57 acting as a piston in the tube 58. However, the pressure in this annular space should it build up while the spindle is being extended will not exceed that within the tube 58 because the latter is in communication with the annular space. Alternatively, a cylinder (not shown) of compressed gas, e.g., air, used instead of the powder charge 60, may be released by the action of the plunger 64 to extend the spindle.

A bushing 74 within the tube 58 acts as a stop for the spindle 57 to establish its extended position. This bushing 74 may have a conical inner diameter (FIG. 13) and may be provided with concentric rings 75 adapting it to be deformed as previously described in connection with the embodiment of FIGS. 1 to 7.

The embodiment of FIGS. 8 to 13 may be further provided with'aii enclosure 5 "for the stabilizing fins 34',

as previously described, and may employ a solid spindle as shown, or a hollow spindle having suitable means such as an integral section to form and isolate a chamber comparable to chamber 59 in the embodiment of FIGS. 8 and 13.

FIG. 14 illustrates a further embodiment in which a solid spindle 76 is extended or propelled to the rear by inertia upon firing of the projectile. In this case, in order to facilitate the inertial action, the ratio of the mass of the propelled body (i.e. the spindle 76 and stabilizing fins 77) to the effective sectional area which is exposed to the pressure of propellant gases to urge the body axially is greater than the ratio of the mass of the projectile (less the spindle 76 and stabilizing fins 77) to the effective sectional area thereof exposed to the pressure of propellant gases to fire the projectile. With this arrangement, the inertial effect on the spindle 76 and stabilizing fins 77 will be suflicient to propel this assembly to the rear upon firing. The spindle 76 has an enlarged front end 76 which impacts on a bushing 78 at the base of the projectile to prevent further extension of the spindle. As previously mentioned, the bushing 78 is compressed or deformed us it is engaged by the forward end of the spindle, thereby establishing a braking effect and locking the spindle in place in its extended position. The tube 79 is suitably secured in the projectile as by the threaded engagement 80 and sealing member 81. As shown in FIG. 14, the fins 7'7 are exposed at the rear of the projectile but if desired, an enclosure 52 of the type shown in the previous embodiment may be employed.

In a further embodiment, FIG. 15, a tube 82 has a decreasing diameter as the rear is approached. The forward end of the spindle 83 carries one or more deformable bushings 84 which are operable to be deformed as the spindle 83 is propelled to the rear and the bushings 84 progressively encounter the decreasing diameter of the tube 82. This arrangement serves as the brake to slow the extension of the spindle and also as a stop to establish the extended position of the spindle and to lock the latter in place.

In the embodiment of FIGS. 16 and 17 the spindle 85 is extended by the action of the onrushing atmospheric air encountered by the projectile after it is fired. As shown in FIG. 16 a wheel 86 having blades 87 thereon is suitably fixed to the end of the spindle 85 as by the thread engagement 88. After the projectile is fired the onrushing air engages the blades 87, exerting a pulling force on the wheel 86 to pull the spindle 85 from the projectile. The threaded engagement S8 of the wheel 86 with the spindle 85 may be such that the wheel 86 will be rotated by the onrushing air to completely unthread itself from the spindle 85 after the latter has been withdrawn so that it will not add any further resistance to the flight of the projectile through the atmosphere. Alternatively, the Wheel may be adapted to break up after the spindle has been withdrawn.

In the embodiment of FIG. 18 the spindle 89 carries a helical ridge 90 slidably engaged in a cooperating slot (not shown) in the rear bushing (not shown, but com parable to bushing 40 in FIG. 6) in the tube. With this arrangement, it will be evident that the spindle 89 will rotate relative to the projectile as it is extended. The helical ridge may be designed to rotate the spindle 45 so that the stabilizing fins 91 will be spaced 45 relative to the slots 92 in the cross-type enclosure, previously described, at the rear of the projectile thereby removing the stabilizing fins 91 from the perturbational zones of air fiow in the rear of the cross.

The modified form in FIG. 19 shows a telescopic arrangement for extending the stabilizing fins further to the rear of the projectile, for example to a distance greater than the axial length of the projectile. In this arrangement, the tube 93 carries slidable cylinder 93', the latter in turn slidably carrying the spindle 94. Suitable guide "bushings'and stops are provided as at 96 and 97'to guide and stop the cylinder 93 in the tube 93 as the cylinder 93' is extended and at 98 and 99 to guide the spindle 94 in the cylinder 93' as the spindle is extended.

Suitable means such as a wad (not shown) of protective material may be placed in the gun barrel between the propellant charge and the projectile to protect the fins of the latter upon firing. Also, a cap may be provided at the rear end of the projectile. The cap may be shaped as a cross, for example, to enclose the slots 56 in the FIG. 1 embodiment.

It will be understood that various changes may be made in the form, construction and arrangement of the several parts without departing from the spirit and scope of the invention, and hence I do not intend to be limited to the details shown or described except as the same are included in the claims or may be required by disclosures of the prior art.

What I claim is:

1. A projectile comprising a body having an axial tube therein, movable means housed at least partially in said axial tube, stabilizing surfaces carried by said movable means, operable means for extending said movable means from the rear of the projectile after the latter has been fired such that the stabilizing surfaces are supported rearwardly of the projectile for guiding the latter in flight,

the radially outward edges of said stabilizing surfaces' being contained within a circumference no greater than that of the projectile body, said movable means comprising a spindle slidable in said axial tube, said spindle having an enlarged portion operable to engage a bushing carried in said axial tube to stop the spindle in its extended position, said bushing having a longitudinal passage for releasing a braking fluid contained in the axial tube exteriorly of the spindle as the enlarged portion on the spindle acts on the braking fluid upon extension of the spindle rearwardly of the projectile.

2. A projectile adapted to be fired from a hollow bore barrel with a propellant charge, comprising a body having a base, an explosive, incendiary charge or the like in said body, an axial tube in said body afiixed to said base and having its interior sealed from said explosive charge, a spindle slidably mounted in said tube and carrying stabilizing fins, said spindle being housed in said tube before the firing of the projectile, said spindle having a passage communicating with the interior of said tube and with the hollow bore barrel thereby to transmit fluid pressure of the propellant charge to the tube to thereby extend the spindle after the projectile has left the barrel, and cooperable means on said axial tube and said spindle to provide a sliding seal to facilitate extension of the spindle by said fluid pressure and to thereafter stop and support the spindle in its extended position.

3. A projectile according to claim 2 wherein said projectile is provided with an enclosure at the rear thereof housing said stabilizing surfaces, said enclosure having intersecting slots formed as a cross, said cross being adapted to reduce the aerodynamic turbulence at the rear of the projectile.

4. A projectile according to claim 2 further comprising means for releasing a braking fluid from the tube as the spindle extends rearwardly of the projectile.

5. A projectile according to claim 2 wherein said cooperable means comprises a bushing on said tube and an enlarged portion on said spindle forming a sliding seal with said tube, said bushing being made of a material adapted to be deformed by said enlarged portion upon completion of the sealing function of the latter.

6. A projectile according to claim 5 wherein said bushing is provided with means defining a longitudinally extending slot through Which said braking fluid is expelled during extension of the spindle.

7. A projectile according to claim 5 wherein said bushing has grooves to facilitate deformation thereof.

References Cited bv the Examiner 5 UNITED STATES PATENTS 1,257,126 2/1918 Schneider lO250 2,426,239 8/1947 Renner 1025O X 2,821,924 2/1958 Hansen et al. 10250 10 SAMUEL FEINBERG, Primary Examiner.

BENJAMIN A. BORCHELT, Examiner.

V. R. PENDEGRASS, Assistant Examiner. 

1. A PROJECTIBLE COMPRISING A BODY HAVING AN AXIAL TUBE THEREIN, MOVABLE MEANS HOUSED AT LEAST PARTIALLY IN SAID AXIAL TUBE, STABILIZING SURFACES CARRIED BY SAID MOVABLE MEANS, OPERABLE MEANS FOR EXTENDING SAID MOVABLE MEANS FROM THE REAR OF THE PROJECTIBLE AFTER THE LATTER HAS BEEN FIRED SUCH THAT THE STABILIZING SURFACES ARE SUPPORTED REARWARDLY OF THE PROJECTIBLE FOR GUIDING THE LATTER IN FLIGHT, THE RADIALLY OUTWARD EDGES OF SAID STABILIZING SURFACES BEING CONTAINED WITHIN A CIRCUMFERENCE NO GREATER THAN THAT OF THE PROJECTIBLE BODY, SAID MOVABLE MEANS COMPRISING A SPINDLE SLIDABLE IN SAID AXIAL TUBE, SAID SPINDLE HAVING AN ENLARGED PORTION OPERABLE TO ENGAGE A BUSHING CARRIED IN SAID AXIAL TUBE TO STOP THE SPINDLE IN ITS EXTENDED POSITION, SAID BUSHING HAVING A LONGITUDINAL PASSAGE FOR RELEASING A BRAKING FLUID CONTAINED IN THE AXIAL TUBE EXTERIORLY OF THE SPINDLE AS THE ENLARGED PORTION ON THE SPINDLE ACTS ON THE BRAKING FLUID UPON EXTENSION OF THE SPINDLE WARDLY OF THE PROJECTILE. 